1. Field of the Invention
The present invention relates a foldable mobile terminal device in which an upper casing and a lower casing are rotatably coupled.
2. Description of the Related Art
In recent years, the mobile phone is equipped with a camera function for photographing subjects, a browser function for browsing web sites, a television function for viewing television programs and so on, in addition to a standard talking function, a transmission/reception function for electronic mails, etc. The mobile phone has been used not only as means for performing communications, but also has been used, among people of all ages, as one's own multifunctional terminal that substitutes for a digital camera, personal computer, and television.
However, although usual televisions or personal computers have a display screen with a horizontally elongated shape, mobile phone terminals typically have a vertically elongated shape on a whole, and the display screen thereof has also a vertically elongated shape in order to improve holdability or operability by one hand. As a consequence, when a horizontally elongated shaped image displayed on a television or personal computer is browsed by the mobile telephone, the image is often displayed by reducing its size in keeping with the display screen of a vertically elongated shape, or the image is often displayed sideways with respect to the display screen and a user browses the image by holding sideways the mobile phone. This raises a problem that either of the size of an image and the holdability of the mobile phone becomes victim to the other.
Japanese Unexamined Patent Application Publication No. 2003-319043 discloses a foldable mobile phone including an upper casing having a display screen, a lower casing having an operator, and a support casing that is hingedly connected to the lower casing and that supports the upper casing so as to be able to rotate the upper casing in the left/right direction about a shaft.
However, as shown in FIG. 2 in the above-described patent document, in order to prevent corners of the upper casing from suffering interference from the hinge when the upper casing is rotated about the shaft provided to the support casing, the lower edge of the upper casing must be significantly curved from its center toward the left and right edge of the upper casing 100A. As a result, in the foldable mobile phone set forth in this patent document, there occurs a problem that the display screen is reduced in size or the design of the device is limited.